package generics;

/**
 * @author Mr.Sun
 * @date 2022年02月21日 20:53
 */
public class LinkedStack<T> {
    private static class Node<U> {
        U item;
        Node<U> next;
        Node() { item = null; next = null; }
        Node(U item, Node<U> next) {
            this.item = item;
            this.next = next;
        }
        boolean end() { return item == null && next == null; }
    }

    // 末端哨兵
    private Node<T> top = new Node<T>();

    public void push(T item) {
        top = new Node<T>(item, top);
    }

    public T pop() {
        T result = top.item;
        if(!top.end())
            top = top.next;
        return result;
    }

    public static void main(String[] args) {
        LinkedStack<String> lss = new LinkedStack<>();
        for(String s : "Phasers on stun!".split(" "))
            lss.push(s);
        String s;
        while((s = lss.pop()) != null)
            System.out.println(s);
    }
}
